1. Field of the Invention
The present invention relates in general to a vertebral stabilization implant. In particular, the present invention relates to a vertebral column dynamic stabilization device that supplements vertebral stabilization via the anterior column and/or the middle column lip and that can also facilitate disc regeneration.
2. Description of Related Art
Each vertebra has a cylindrical-shaped vertebral body in the anterior portion of the spine with an arch of bone to the posterior that covers the neural structures. Between each vertebral body is an intervertebral disk, a cartilaginous cushion to help absorb impact and dampen compressive forces on the spine. To the posterior, the laminar arch covers the neural structures of the spinal cord and nerves for protection. At the junction of the arch and anterior vertebral body are articulations to allow movement of the spine.
When a surgeon is faced with a ruptured disc but not necessarily a severely degenerative segment, traditionally a microdiscectomy is performed where a simple removal of the disc fragment is performed and the fragment is removed from the cord. One problem with this solution is although the endplates of the disc and the lateral portions of the disc may be left intact; there can be a collapse of the spine, with excessive collapse of the interspace in height. This can lead to secondary neural foraminal stenosis.
Other solutions involve flexible rod attachments. For example, a posterior system for the lumbar spine with a pedicle screw base system and a flexible rod attachment is known as the Zimmer Spine Dynesis System. The Zimmer system though is a posterior system and has no application in the cervical spine or for anterior applications.
Recent solutions have looked at the possibility of replacing the disc in an interdiscal position with a motion device, which involves total disc replacement, and there are multiple devices on the market and patented available for this use. Other solutions involve cervical plates that provide rigid stabilization of an anterior column. These concepts aid fusion with a supplementation of stability after a bone graft is placed into the disc space. The stabilization of the vertebra to allow fusion is often assisted by a surgically implanted device to hold the vertebral bodies in proper alignment and allow the bone to heal. However, there are disadvantages to these current stabilization devices.